Control system.



P. L. Mums CONTROL svsnzu.

Patented m 21, 1918.

3 SHEETS-SHEET I INVENTOR Paa/L. Ward/3.

WITNESSES fl ATTORNEY P. L. MARDIS.

CONTROL SYSTEM.

APPLICATION FILED IIAY 3, 1915.

1,266,607. Patented May 21,1918.

3 SHEETS-SHEET 2. 5 7 /0 wfinsssss: 4 INVENTOR W Pau/L/Vard/b".

P. L. MARDIS.

CONTROL SYSTEM.

APPLICAHON mEo MAY 3. 1915.

1,266,607. Patented May 21,1918.

3 SHEETS-SHEET 3.

R #2516. Ms

M/ 9 M4 m, 0 m m "I- 2 0A0) I; n t! In "In 0 u 0 m I WITNESSES INVENTORS Paa/LMard/J:

l ATTORNEY PAUL L. MARDIS, OF ALTOONA, PENNSYLV ANIA, ASSIGNOR TOWESTINGHOUSE ELEC- TRIO AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

common svs'rmir.

Specification of Letters Patent.

Patented May 21, 1918.

Application filed May S, 1915. Serial No. 25,496.

To all whom it may concern:

Be it known that I, PAUL L. MARDIS, a citizen of the United States, anda resident of Alloona, in the county of Blair and State of Pennsylvania,have invented a new and useful'lmprovement in Control Systems, of whichthe following is a specification.

My invention relates to control systems for dynamo-electric machines,and it has special reference to four motor equipments of theseries-parallel type such as are commonly employed upon electric railwayvehic es. One of the objects of my invention is to provide animprovedmethod and means for controlling the operation of a plurality ofmotors constituting a portion of a system of the above-indicatedcharacter, and to provide a simple mode of successively arranging thecircuit connections of the motors for series, series-parallel andparallel-circuit operation, whilenmaintaining a unidirectional flow ofcurrent through the motors during the circuit changes.

Another object of my invention is to provide a method and means forcontrolling a four-motor equipment of the general class referred towhich shall be adapted to disconnect each of the respective motors fromthe system during the several steps by which the motors are acceleratedto their full-speed operation, whereby each of the motors is permittedto remain idle for a portion of.

the accelerating period.

Another object of my invention is to provide a method nd means forchanging the several motors from series-parallel groups intofull-parallel-circuit relation through an intermediate step in which asingle motor is connected in parallel with two motors that are connectedin series-circuit relation, and, moreover, for effecting these changesin circuit connections without reversing the current in any of themotors.

In the prior art'yit has heretofore been proposed to provide a systemand mode of control of somewhat similar characteristics, but, in allsuch systems with which 1 am familiar, the desired circuit changes areeffected at the expense of reversing the direction of flow of thecurrent in certain of the motors, and the motors are not workeduniformly during the acceleration period, cer- I tain of the motorsbeing actively in circuit throughout the entire acceleration, whileother motors are permitted to be idle to some extent.

According to my invention, I propose to Improve and simplify the systemsof the prior art, to overcome the difficulties and deficiencies incidentto other systems and to secure'the advantages and benefits hereinbeforeenumerated.

My invention is illustrated in the accompanying drawings in which Figure1 is a diagrammatic view of the main circuit connections and maincontrol apparatus of a s stem of control embodying my invention;

i'g. 2 is a sequence chart indicating the positions of the severalswitches in different steps of the controller; Fig. 3 is a diagrammaticview of the auxiliary control circuit connections and the auxiliarycontrol circuit apparatus which is employed for governing the operationof the main circuit apparatus shown in Fig. 1; Fig. simplified view ofthe main rcuit connections of the motors that are stablished in certainsteps of the controller; and Figs. 5 and 6 are, respectively, viewscorresponding to Figs. 2 and 4 of a. modified form of control s stemembodying my invention.

Re erring to Fig. 1, a plurality of series motors M1, M2, M3 and M4 areadapted to receive energy IIOID'JL'SUPPIY circuit, one member of whichcomprises a trolley condoctor 1 and the other, a ground G, throu h aresistor R and a plurality of electricafiy operated motor-circuitswitches a, b, c, d, e, f, g, h, i, j, and k, which are adapted toarrange the circuit connections of the several motors for series,series-parallel and full-parallel operation. v

The several unit switches maybe of any well-known construction and eachcomprises an energizing coil 3, a movable magnetlzable core 4, a movableswitch member 5 and a plurality of stationary contact terminals 6 whichare adapted for cooperative engagement, while some of the unit switchesreferred to are provided with interlock switches 7 by means of whichcertain of the control circuits are interlocked and a predeterminedsequence of operation is obtained. The unit switches may be, andpreferably are, of the well-known electro-pneumatic type.

4 is a diagrammatic the several unit switches will be referred to, as awhole, by their reference characters and no attempt will be made todesignate the component parts of each switch with separate referencecharacters.

It will, of course, be understood that each of the switches is adaptedto occupy two positions, an in position, in which the switch isenergized and closed, and an out" position, in which it isde'cinergizedaml opened. The interlock switches associated with theseveral unit switches will be denoted by means of the referencecharacter of the unit switch with which it is associated, followed bythe word in or out, which indicates the position in which the interlockswitch is closed. For instance, interlock switch i--out indicates thatthe interlock switch associated with the unit switch i is closed whensaid unit switch occupies its open or out position.

Referring now to Fig. 3, a master controller MO is shown, whichcomprises a movableicontact member 10 of peculiar configuration and aplurality of stationary contact terminals 13+, (1,, b, c, (l, c, f, g,k,

i, j and is that are adapted to be engagedoy the movable contact member10 along the position-indicating lines 1, 2, 3, 4, 5, 6, 7 and 8 for thepurpose of establishing suitable circuits from a battery B, or othersource of energy, through the energizing coils of the several unitswitches a to is, inclusive.

Assumin the apparatus and circuit connections to be as shown, theoperation of the system is as follows: The master controller BIC isfirst moved into its osition 1 in which a circuit is established rom thepositive side of the battery B which includes stationary contactterminal B+ and movable conductin segment 10 of the master controller Mwhere the circuit divides, one branch including contact terminal a andenergizing coil. of switch a and thence to a conductor B which connectsto the negative side of the battery; another circuit traverses contactterminal bf, energizing coil of switch 6, and interlock switch z'out tothe B conductor; another circuit traverses stationary contact terminals0', energizing coil of switch 0, and interlock switch 7out to the B-conductor, and a fourth branch includes contact terminal d, energizingcoil of switch d, and interlock switch k-out to the B- conductor.

Having established the circuits just traced, the several unit switchesa, b, c, and cl are energized and closed. Thus, energy is supplied fromthesupply-circuit conductor Z through trolley T, switch a, resistor R,motor M1, switch 12, motor M2, switch 0, inotor M3, switch (1, and motorM4 to the return circuit G. The'several motors M1, M2, M3, and M4 andresistor R are thus connected in sr -ies-circuit relation, as shown instep 1. in Fig. 4, and, being supplied with energy, are started intooperation at slow speed.

When the master controller MC is moved to its position 2, anothercircuit is established from the movable contact member 10 throu hcontact terminal e and energizing coil 0? switch 1: to the conductor B.The switch e isftherefore, energized and closed to short'circuit theaccelerating resistor R,

thereby causing the motors to increase in speed, the circuit connectionsbeing as shown in step 2 of Fig. 4.

During the next step of the controller MC, circuits are established fromconducting member 10 through contact terminal h and energizing coil ofswitch it to conduc tor B, and through contact terminal i, andenergizing coil of switch 2' to the interlock switch b-out. The switchit is thus energized and closed, although switch '11 is not energized,inasmuch as its circuit is broken by the interlock switch bout, switch 6being still held in its in or closed position. Immediately subsequent tothis action, the stationary contact terminals b and d become disengagedfrom the movable conducting member 10 and, therefore, the correspondingswitches b and (l are denergized and permitted to open. As soon as'the-switch 6 drops into its out position, its interlock switch boutcompletes the energizing circuit of the switch i, and said switchimmediately is closed.

The main circuit through the motors is then as follows: from trolley Tthrough, switch a, switch e, motor M1, switch i, switch 0, switch it andmotor M4 to the ground G, as shown in step 3 of Fi 4. Motors M2 and M3are disconnected rom active circuit and are permitted to remain idle.

As the master controller is moved into position 4, circuits areestablished from contact member 10 through contact terminal f andenergizing coil of switch f to conductor B,- and through contactterminal energizing coil of switch is and interlock switch dout to theB- conductor. Switches f and here thus energized and closed, therebyconnecting the several motors M1, M2, M3 and M4 in series-parallelgroups, as indicatedin step 4 of Fig. 4.

The new motor circuit established by the closure of the switches 'ustreferred to, supplies ener to motors 1 and M4 through a circuit mm thetrolley through switch f, motor M2, switch a, motor M3 and switch is toound G.

etween positions or steps 4 and 5 of the master controller MC, there area plurality of transition notches 4a, 4b, 4c and 4d, as

indicated in the chart shown in Fi 2, for the purpose of effecting thetransition of motor-clrcuit connections from the. seriesparallelrelation lished in position step or position 5 of the motor current.suitable transition connections may be ployed between steps 4 of themotors, as estab 4, to the next operative without the interruptionInasmuch as any and 5, so long as the motor circuits are not interruptedand a unidirectional flow of current through the motors is maintained, Ido not deem it necessary to trace the circuit connections of the varioustransition notches.

Therefore,

a description of the transition connections will be omitted and theconnections established in the next running position 5 will beconsidered.

In this position, the movable conducting member 10 is in engagement withthe following stationary contact tcrminals B|, a,

b e, g, j and k and, therefore, the responding switches a, b, c, g, j,and is closed to establish the arrangement of tors indicated in step 5of Fig. 4. The circuit connections are as follows: from trolley Tthrough switch the circuit divides In the step 6 of the controllerMC,sta

contact terminal h and its cormtiona spending switch understood.

a a h is energmed, as Wll a, and switche, where one branch including themotor M1,'sw1tch 6, motor M2, an

ther and lbe The switch h, therefore, is

closed and connects the motor M4 in parallel with the motor M3, both ofwhich ar ein multiple-circuit relation with the motors M1 and M2 Thearrangement of circuit connections motors is shown in step 6 of Fig. 4.

In moving the master controller to its sition 7, contact terminal bwhich are in series with each other.

and

becomes disengaged from the movable conducting member 10 and, hence, theswitch 6 and opened. Concurrently,

is denergized therewith, howi ever, contact terminal f becomes energizedand its corresponding switch f closed. Thus,

the motor M1 is disconnected from the tem and is idle, while motor M2 isconne in parallel lel-connected motors M3 and M4. The

syscted relation with the other two paralcircuit connections are then asshown in step 7 of Fi ."4.

Ast its last is closed to conncct the motor M1 in par with the othermotors M2,

M3 and e master controller MC is moved into position 8, contact terminal2 becomes disengaged and its corresponding switch a allel M4,

whereby the full-parallel arrangement of the motors is established.

Throughout the operation, set forth, it is manifest that, reversal inthe direction of through any of the motors cfi'ected, but aunidirectional flow thereof is mainta at no time,

as hereinbefore isa flow of current that ined nections for fnl Moreover,each one of the sevat all times.

motors is disconnected from the era! driving system and permitted to beidle for a certain Reference may now be had to Figs. 5 and p a modifiedform of my invention in which the sequence of the switches shown in Fig.1 is so fixed as to effect the changes in circuit connections fromseriescireuit relation to full-parallel relation while maintaining aunidirectional flow 0 current through said motors throughout the circuitchanges.

In step 1, switches a, b, c, and rl are closed and the motors M1, M2, M3and M4 and the starting resistor R are connected in seriescircuitrelation. as shown in step 1 of Fig. 6.

In step 2,switch c is also closed to shortcircuit the resistor R andexclude it from the motor circuit.

In step 3, switch G is closed and switch 0 opened, thereby disconnectingthe motors M1 and M2 and connecting motors M3 and M4 in series circuitdirectly across the source of ener;

Switch J is closed in position 4 to connect the negative side of themotors M1 and M2 ttrground, thereby establishing a seriesparallelgrouping of the'motors.

In the next or transition position, switch I) is opened and switch fclosed. Thus, the motor M1 is disconnected from circuit and motor M2 isconnected in parallel-circuit relation to motors M3 and M4 which areconnected in series circuit with each other.

ln step 5, switch c is opened and switch 2' closed, thereby temporarilyinserting the resistor R and connecting the motor M1 in parallel withthe motor M2, said motors being arranged in n'lultiple-circuit relation6 which disclose with the series-connected motors M3 and M4.

In step 6, switch 0 is again closed to incl ude the resistor R, theother circuit connections remaining unchanged.

In step 7. switch rl is opened and switch 1.: closed. Thus, the motorsM1, M2 and M3 are connected in multiple relation and motor M4 isdisconnected from the system.

In the last step, step 8, switch It is closed to connect the motor M4 inparallel with the other motors, thereby establishing con- -paralleloperation.

By reason of the fact that a master controller andauxiliary-control-ciicuit connections have been fully set forth inconnection with the system first described, and also, inasmuchas it isbelieved that no difliculty will be experienced by those skilled in theart in understandingthe mode of operation and circuit connections of themodified form of my invention just described, I have deemed itunnecessary to illustrate a master controller for the purpose ofgoverning the several switches to secure a sequence of operation thereofin accordance with the chart shown in Fig. 5, whereby the circuitconnections shown in Fig. 6 are established.

It is manifest, of course, that various modifications in the arrangementof circuit connections and mode of operation may be effected withoutdeparting from the spirit and scope of my invention, and suchmodifications are intended to be covered by the appended claims.

I claim as my invention:

1. The method of controlling four electric motors which consists inconnecting said motors in series relation, disconnecting two of themotors from circuit, connecting the motors in series-parallel groups,connecting two of the motors in series-circuit and in parallel relationto a single motor and connecting the motors in full-parallel relation,while maintaining a unidirectional flow of current during the changes.

2. In a system of control, thecombination with four motors, of controlapparatus associated therewith for arranging the circuit connections ofthe several motors to change the motors from series to parallelrelations and to eflect the changes by successively establishing as manyparallel paths throng the motors as there are motors, while maintainingthe flow of current through each of the active motors unchanged, saidchanges including one transition step wherein two series-connectedmotors are in multiple circu with a single motor.

3. In a system of control, the combination with a plurality of motors,of means comprising control apparatus and circuit connections forconnecting the motors in series, in series-parallel and in arallelrelation, and means for disconnectrn each of said motors from circuitduring t e acceleration from series to parallel relation and formaintaining at least two of said motors in circuit throughout thechanges.

4. The method of chan ing four electric motors from series-parallerelation to fullparallel relation, which consists in first cutting-outone of the said motors, leaving one motor in parallel with the two whichare in series, then reconnecting the motor which is cut-out in parallelwith the remaining motors, then cuttin -out one of the two motors inseries, an finally connecting the last motor cut-out in parallel withthe others, while maintaining a unidirectional flow. of current throughthe respective m'otors.

5. In a control system, the combination with a plurality of motors, ofcontrol apparatus for first connecting all of the motors in seriesrelation, then connecting them in series-parallel groups, and finallyall in parallel relation, said control apparatus comprising rclafivelymovable contact members and circuit connections arranged to disconnectthe motors one after another from circuit, while effecting the motorcircuit changes and to maintain a unidirectional flow of current throughthe respective motors.

6. In a system of control, the combination with a plurality of electricmotors, of control apparatus comprising contact members and circuitconnections for changing the motors from series-parallel relation tofullparallel relation, said contact members and connections beingadapted to successively disconnect the motors, one after another, formcircuit, and to maintain .a unidirectional flow of current tln-nugh theactive motors duri ng the circuit changes.

7. The method of control of four electric motors, which consists inconnecting all of said motors in series-parallel groups, then connectingtwo series-connected motors in multiple circuit with a single-motor, andthen connecting all of the motors in parallelcircuit relation, whilemaintaining a uni-.

directional flow of current through said motors during the operation.

S. The method of controlling four electric motors, which consists insuccessively fionnet-ting the motors in series-circuit relation, inseriesparallel groups and in full-pan ,allcl-circuit relation, whileidling all of said motors at. different times during the changes inconnections.

9. The method of controlling four electric inotors, which consists insuccessively connecting said motors in series-circuit relation and thenin full-parallel-circut relation, while disconnectin all of the motorsfrom circuit and idling t e same at different times during the changesin connections.

10. In a system of control, the combination with a plurality of electricmotors, of control apparatus and circuit connections for successivelyconnecting the motors in series-circuit relation, in serics-parallelgroups and in full-parallel-circuit relation, while disconnecting all ofthe motors from the system at different tilnesand allowing them toremain idle; during the circuit changes.

In testimony whereof, I hays hereunto subscribed my name this 27th dayof April,

PAUL L. MARDIS. Witnesses:

ALEX Warn, PERRY H. WEDGE.

